Keeping Your PC Cool

As I recounted in an earlier post, my friend Dave’s PC recently died (or was killed, depending on whether you talk to him or me). Rather than let the PC’s carcass go the waste, I salvaged the surviving components and have been rebuilding the PC.

When I took the dead PC apart, I examined it to determine the cause of death. While the specific computer (a Gateway media center PC) seemed to be prone to problems, one main factor seems to have been heat. Three of the graphic card’s capacitors had ruptured, the case only had one fan for the CPU and the grill for that fan was packed with pet hair and dust.

Those of you who have played the Battletech games (the tabletop or video game versions) know that heat is bad for mechs. The same is true for PCs. Excess heat causes PCs to run erratically, crash and can even cause damage to the hardware. In some cases, the damage is gradual and leads to a premature PC death. In other cases, the heat damage can be quite dramatic, such as capacitors exploding with a snap, crackle and pop.

Fortunately, keeping your PC cool can be fairly easy. Those who are technical and build their own systems know the tricks and techniques for staying cool. As such, this essay is aimed at a more general audience.

The first and cheapest method is keeping your PC clean. Dust builds up in PC cases, on components and in fans. If you have furry pets, their fur will almost certainly get into your PC case. To deal with this, turn off your PC and open the case. Compressed air cans are useful for blowing the dust and crud out of the grills and fans. Be sure to blow the crud out of the case rather than into the case. A small vacuum can be useful for cleaning out the case itself and cleaning components. You should be very careful when cleaning the components to avoid damaging them (or yourself). Obviously, cleaning fluids should generally not be used on electronics (I have actually been asked about this).

Second, be sure to position your PC properly. The key is to have “air space” around your PC, most especially the back and front. This helps the PC vent heat. Some computer desks have a enclosed area for the PC. Putting your PC in those areas can impede its ability to vent heat. Also, keeping your PC off the floor can help protect it from dust, pet hair and other debris. Naturally, a PC should be located in as clean and cool a place as possible.

Third, there is the matter of case airflow. Most PCs are like a snakes’ nest inside with cables everywhere. Cables, especially those big IDE ribbon cables, can block air flow within the case and increase heat problems. Airflow can be improved my managing these cables. Unused cables from the power supply can be coiled up and secured, thus helping to get them out of the way. You can also position the cables that are in use so that they block the airflow less. Some cases have cable clips that allow you to run the cables against the side of the case and this can improve air flow. Be careful when moving the cables around to avoid detaching them or damaging components.

Fourth, adding or replacing fans in your case can improve your PC’s cooling capacity. Not surprisingly, PC manufacturers prefer to save money and tend to use lower end fans in their consumer models. It is also common for PC manufacturers to use the minimum number of fans. For example, Dave’s dead PC just had a CPU fan and no case fan. Most cases do have a place to add a fan (look for a grill on the back of the case). If you do not have a fan in your case, it can be a very good idea to add one. If you have added a video card or other components to your PC, you will want to have a good case fan.

When picking a fan, you will need to first determine the size of the fan. While case fans come in a variety of sizes, the most common fan is 80mm. 120mm fans are less common, but some large cases support them. To determine the fan size for your case, find the fan grill/hole. There will be (or should be) four holes around the grill. Measure from the top left hole to the bottom left hole (or right, it doesn’t matter). Unlike monitors (which are measured diagonally to make them seem bigger), case fans are measured top to bottom or side to side.

Once you find your fan size, you’ll need to decide how powerful and how quiet a fan you will need. Fans range from quiet models that move little air to really loud models that blast. Most fan manufacturers list the noise of the fan in decibels (more is louder) and the amount of air the fan moves (more is better). RPMs can be important, but a fan that is bigger and slower might move more air than a fan that is faster and smaller. In general, more RPM means more noise. Some fans are actually designed to be less noisy and noise can be reduced by using noise absorbing pads where the fan mounts on the case (be sure that they do not block the fan-it is best to use those that come with the fan or are made for it).

If you want to be a bit more fancy about your fan, you can get models with neon lighting, heat sensors, manual speed settings and other features.

Regardless of which fan you get, you will need to install it (or get someone else to it). Putting in a fan is fairly easy. You’ll need to turn off your PC and open the case (of course). Fans are generally held in place by four screws (one in each corner). Be sure to mount the fan facing the right way (either pulling air into the case or blowing air out). Check to see that the fan is secure (having a running fan fall into your case could be a bad thing). Once the fan is secure, it will need to be powered. Most fans have a small connector that plugs into three pins on the motherboard. Most motherboards label the fan connectors with “fan pwr” but some do not. If you do not know what a connector might be, don’t plug the fan into it. Powerful fans often have to be plugged into the power supply directly using a standard four pin connector (the sort used to power DVD, CD and older hard drives). Once the fan is plugged in, you can test it by starting up your system. When you are sure everything is working well, shut it down and close the case up.

New Egg is an excellent place to buy fans. They list the relevant statistics for each fan and have extensive customer evaluations of these fans.

You can also improve your PC’s cooling capacity by replacing the CPU cooling system. This is more involved than adding a case fan and doing it wrong can cause serious problems for your PC. If you chose to do this, be sure to match the cooling system with your CPU type or there will probably be problems. Some cooling systems are passive heat sinks, others have fans and some use liquid cooling. Whatever type you use, proper installation is critical. CPUs generate a great deal of heat and will be damaged or destroyed if the cooling system is not working properly. In general, it is best not to mess with your CPU cooling system unless you need to and you know what you are doing. If you think thermal paste is a sexual aid, then you should stay away from your CPU cooling system.

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I resent the accusation that my PC was filthy – I dunked it in soapy water at least once a month! Seriously – good article, Mike. I just assumed my PC had a proper fan. I’ve never heard of a case fan. I’ve also never had a PC overheat from pet hair but I’ve never had this many pets before either (I now have two cats and a stepdog, and my wife seems determine to add to the menagerie).
Dave

I’ve seen worse. About 10 years ago I did a memory upgrade for another professor and his PC had roving gangs of dust bunnies inside the case. They were fighting for turf and worshiping the CPU. Naturally, they were struck down for their theology.